BZOJ2563 阿狸和桃子的游戏

Posted 2020-10-30 ^m

题意：n个点m条边的图，有点权和边权，两个人轮流选点染色，每个人的得分为点权和加上所选点之间的边权和，问两人都最优策略时先手得分减去后手得分

边权分成两半，分别加到两个端点上，若两点同色则为一人得分，不同色则对两人得分贡献相同，计算得分差可以抵消

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<cmath>
 5 #include<cstring>
 6 #include<vector>
 7  
 8 using namespace std;
 9 
10 const int MAXN = 11000;
11 int n, m;
12 double w[MAXN];
13 
14 template <typename tn> void read (tn & a) {
15     tn x = 0, f = 1;
16     char c = getchar();
17     while (c < ‘0‘ || c > ‘9‘){ if (c == ‘-‘) f = -1; c = getchar(); }
18     while (c >= ‘0‘ && c <= ‘9‘){ x = x * 10 + c - ‘0‘; c = getchar(); }
19     a = f == 1 ? x : -x;
20 }
21 
22 int main() {
23     read(n);
24     read(m);
25     for (int i = 1; i <= n; ++i) read(w[i]);
26     while (m--) {
27         int u, v;
28         double l;
29         read(u);
30         read(v);
31         read(l);
32         l /= (double) 2;
33         w[u] += l;
34         w[v] += l;
35     }
36     sort(w + 1, w + 1 + n);
37     double x = 0, y = 0;
38     for (int i = n; i > 0; i -= 2) {
39         x += w[i];
40         y += w[i - 1];
41     }
42     x -= y;
43     printf("%.0f\n", x);
44     return 0;
45 } 

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